Many multi-speed automatically shifted power transmissions utilize electro-hydraulic controls. There are instances under which the electronic controls or electronic service may be discontinued for many reasons. When this occurs, it is desirable to permit the transmission to operate in at least one forward mode and one reverse mode to permit the operator to return the vehicle to a service location where the electrical problem might be repaired.
In many of these transmissions, the electrical controls include a plurality of solenoid valves which control the shifting of the transmission. The electrical discontinuance therefore affects all of the shifting controls, such that at least one hydraulic path must be provided for the desired forward ratio and reverse ratio.